Journo is search of a narrative that isn't there. McDonalds could stop tracking customers tomorrow and people would still be eating the same food there in 50 years.
The secret sauce is has more to do with actual sauce than anything claimed here.
McDonalds is currently 46,000, 13k of those in the US alone. It's just not even comparable.
Nobody's too big to fail, and the way you fail is by making no innovation in your business, not doing optimizations that smarter competitors do, etc. (which was exactly what Kmart spent the 80s and 90s doing).
McDonald's would absolutely decline if they simply abandoned all 'loyalty program' ideas, while every competitor leverages them, because those competitors will take customers away little by little. Fewer customers, less money to justify renovations, less people want to open new franchises in the best spots, leading to fewer customers, in a cycle.
[1] https://www.reddit.com/r/kmart/comments/1jiusko/the_last_us_...